Akt2 regulates Rac1 activity in the insulin-dependent signaling pathway leading to GLUT4 translocation to the plasma membrane in skeletal muscle cells

2013 ◽  
Vol 25 (6) ◽  
pp. 1361-1371 ◽  
Author(s):  
Shinsuke Nozaki ◽  
Tomoya Takeda ◽  
Takuya Kitaura ◽  
Nobuyuki Takenaka ◽  
Tohru Kataoka ◽  
...  
Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3129
Author(s):  
Jyotsana Pandey ◽  
Kapil Dev ◽  
Sourav Chattopadhyay ◽  
Sleman Kadan ◽  
Tanuj Sharma ◽  
...  

Estrogenic molecules have been reported to regulate glucose homeostasis and may be beneficial for diabetes management. Here, we investigated the estrogenic effect of β-sitosterol-3-O-D-glucopyranoside (BSD), isolated from the fruits of Cupressus sempervirens and monitored its ability to regulate glucose utilization in skeletal muscle cells. BSD stimulated ERE-mediated luciferase activity in both ERα and ERβ-ERE luc expression system with greater response through ERβ in HEK-293T cells, and induced the expression of estrogen-regulated genes in estrogen responsive MCF-7 cells. In silico docking and molecular interaction studies revealed the affinity and interaction of BSD with ERβ through hydrophobic interaction and hydrogen bond pairing. Furthermore, prolonged exposure of L6-GLUT4myc myotubes to BSD raised the glucose uptake under basal conditions without affecting the insulin-stimulated glucose uptake, the effect associated with enhanced translocation of GLUT4 to the cell periphery. The BSD-mediated biological response to increase GLUT4 translocation was obliterated by PI-3-K inhibitor wortmannin, and BSD significantly increased the phosphorylation of AKT (Ser-473). Moreover, BSD-induced GLUT4 translocation was prevented in the presence of fulvestrant. Our findings reveal the estrogenic activity of BSD to stimulate glucose utilization in skeletal muscle cells via PI-3K/AKT-dependent mechanism.


2018 ◽  
Vol 1864 (5) ◽  
pp. 1653-1662 ◽  
Author(s):  
Mario Navarro-Marquez ◽  
Natalia Torrealba ◽  
Rodrigo Troncoso ◽  
Cesar Vásquez-Trincado ◽  
Marcelo Rodriguez ◽  
...  

Author(s):  
Abraham Giacoman-Martínez ◽  
Francisco Javier Alarcón-Aguilar ◽  
Alejandro Zamilpa-Alvarez ◽  
Fengyang Huang ◽  
Rodrigo Romero ◽  
...  

α-amyrin, a natural pentacyclic triterpene, have anti-hyperglycemic effect in mice and dual PPARδ/γ action in 3T3-L1 adipocytes, and potential in the control of type 2 diabetes (T2D). About 80% of glucose uptake occurs in skeletal muscle cells, playing a significant role in IR and T2D. Peroxisome-proliferator activated receptors (PPARs), in particular PPARδ and PPARγ, are involved in the regulation of lipids and carbohydrates and, along adenosine-monophosphate (AMP)-activated protein kinase (AMPK) and protein kinase B (Akt/PKB), are implicated in translocation of glucose transporter 4 (GLUT4). However, it is still unknown whether α-amyrin can affect these pathways in skeletal muscle cells. The work's objective was to determine the action of α-amyrin in PPARδ, PPARγ, AMPK, and Akt/PKB in C2C12 myoblasts. The expression of PPARδ, PPARγ, FATP, and GLUT4 was quantified using RT-qPCR and Western blot. α-amyrin increased these markers along with p-AMPK but not p-Akt/PKB. Molecular docking showed that α-amyrin acts as an AMPK-allosteric activator, and may be related to GLUT4 translocation, evidenced by confocal microscopy. These data support that α-amyrin could have an insulin-mimetic action in C2C12 myoblasts and should be considered as a bioactive molecule for new multitarget drugs with utility in T2D and other metabolic diseases.


2014 ◽  
Vol 306 (9) ◽  
pp. E1065-E1076 ◽  
Author(s):  
Hidemitsu Sakagami ◽  
Yuichi Makino ◽  
Katsutoshi Mizumoto ◽  
Tsubasa Isoe ◽  
Yasutaka Takeda ◽  
...  

Defects in glucose uptake by the skeletal muscle cause diseases linked to metabolic disturbance such as type 2 diabetes. The molecular mechanism determining glucose disposal in the skeletal muscle in response to cellular stimuli including insulin, however, remains largely unknown. The hypoxia-inducible factor-1α (HIF-1α) is a transcription factor operating in the cellular adaptive response to hypoxic conditions. Recent studies have uncovered pleiotropic actions of HIF-1α in the homeostatic response to various cellular stimuli, including insulin under normoxic conditions. Thus we hypothesized HIF-1α is involved in the regulation of glucose metabolism stimulated by insulin in the skeletal muscle. To this end, we generated C2C12myocytes in which HIF-1α is knocked down by short-hairpin RNA and examined the intracellular signaling cascade and glucose uptake subsequent to insulin stimulation. Knockdown of HIF-1α expression in the skeletal muscle cells resulted in abrogation of insulin-stimulated glucose uptake associated with impaired mobilization of glucose transporter 4 (GLUT4) to the plasma membrane. Such defect seemed to be caused by reduced phosphorylation of the protein kinase B substrate of 160 kDa (AS160). AS160 phosphorylation and GLUT4 translocation by AMP-activated protein kinase activation were abrogated as well. In addition, expression of the constitutively active mutant of HIF-1α (CA-HIF-1α) or upregulation of endogenous HIF-1α in C2C12cells shows AS160 phosphorylation comparable to the insulin-stimulated level even in the absence of insulin. Accordingly GLUT4 translocation was increased in the cells expressing CA-HIF1α. Taken together, HIF-1α is a determinant for GLUT4-mediated glucose uptake in the skeletal muscle cells thus as a possible target to alleviate impaired glucose metabolism in, e.g., type 2 diabetes.


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